1. Field of the Invention
The present invention relates to a flexible interconnecting substrate and a method of fabrication thereof, a film carrier, a tape-shaped semiconductor device, a semiconductor device, a circuit board, together with electronic equipment.
2. Description of the Related Art
Tape automated bonding (TAB) is known in the art for mounting semiconductor chips onto a flexible interconnecting substrate. This flexible interconnecting substrate often comprises a flexible base substrate of a polyimide and an interconnecting pattern formed by machining a foil copper material on top thereof. Warping is likely to occur in a prior-art flexible interconnecting substrate, due to heating that is applied during heating steps partway through the fabrication. If the base substrate becomes bent, a problem will occur in that the reliability of connections with semiconductor chips or mounting substrates will deteriorate.
The present invention was devised to solve these problems and has as an objective thereof the provision of a flexible interconnecting substrate and a method of manufacturing the same, a film carrier, a tape-shaped semiconductor device, a semiconductor device, a circuit board, and electronic equipment that make it possible to reduce warping of a base substrate.
(1) A flexible interconnecting substrate in accordance with the present invention comprises a tape-shaped base substrate and a plurality of interconnecting patterns formed on the base substrate, wherein:
each of the interconnecting patterns has a plurality of interconnects, and
each of interconnects has a portion extending in a direction of a first side edge of a widthwise direction of the base substrate, and a portion extending in a direction of a second side edge of the widthwise direction of the base substrate, the directions of the first and second side-edges crossing with a longitudinal axis of the base substrate.
Note that in this aspect of the invention, xe2x80x9cinterconnectxe2x80x9d indicates a portion in contact with at least two electrical contact points and xe2x80x9cinterconnecting patternxe2x80x9d indicates all of a plurality of interconnects comprised within one final product (such as a semiconductor device). A flexible interconnecting substrate in accordance with the present invention comprises a plurality of interconnecting patterns for manufacturing a plurality of final products.
With this aspect of the invention, interconnects have portions that extend in the directions of first and second side edges, so that the interconnects provide support in a plurality of directions even if the base substrate expands or contracts, thus making it possible to reduce warping of the base substrate.
(2) With the above described flexible interconnecting substrate,
each of the interconnecting patterns may have a plurality of interconnect portions aligned along an extending direction of the interconnecting patterns, the interconnecting portions comprising regions of plurality types of width being disposed on the base substrate.
This ensures a configuration in which the interconnecting pattern goes obliquely with respect to the direction of extension of the interconnecting pattern, within the region between the interconnecting portions having different width of disposed region. The strength of the material that forms the interconnecting pattern can therefore be increased in directions other than the direction of extension of the interconnecting pattern, and also the bending strength of the base substrate can also be increased. As a result, it is possible to prevent the generation of warping in the base substrate because the interconnecting pattern provides support even when a force that causes warping is applied to the base substrate. Since the interconnecting pattern goes obliquely with respect to the extending direction of the interconnecting pattern, even when the material of the interconnecting pattern and the material of the base substrate have different coefficients of thermal expansion, stress is applied in a direction that the base substrate is difficult to be warped. It is therefore possible to reduce the amount of warping generated in the base substrate.
(3) With the above described flexible interconnecting substrate,
each of the interconnecting patterns may have a plurality of interconnect portions aligned along a longitudinal direction of the base substrate, the interconnecting portions comprising regions of plurality types of width being disposed on the base substrate.
This ensures a configuration in which the interconnecting pattern goes obliquely with respect to the longitudinal direction of the base substrate, within the region between the interconnecting portions having different width of disposed region.
The strength of the material that forms the interconnecting pattern can therefore be increased in directions other than the longitudinal direction of the base substrate, and also the bending strength of the base substrate itself can also be increased. As a result, it is possible to prevent the generation of warping in the base substrate because the interconnecting pattern provides support even when a force that causes warping is applied to the base substrate. Since the interconnecting pattern goes obliquely with respect to the longitudinal direction of the base substrate, even when the material of the interconnecting pattern and the material of the base substrate have different coefficients of thermal expansion, stress is applied in a direction that the base substrate is difficult to be warped. It is therefore possible to reduce the amount of warping generated in the base substrate.
(4) With the above described flexible interconnecting substrate,
one of the interconnect portions may be a wide portion that expands the width of a region disposed on the base substrate between the first and second side edges, and
another of the interconnect portions may be a narrow portion that narrows the width of the region disposed on the base substrate between the first and second side edges.
(5) With the above described flexible interconnecting substrate,
the wide portion may be a maximum of the width of the region disposed on the base substrate, and
the narrow portion may make the width of the region disposed on the base substrate narrower than the width of the wide portion.
(6) With the above described flexible interconnecting substrate,
the narrow portion may have a plurality of direction-changing portions for changing the direction of each of the interconnecting patterns.
(7) With the above described flexible interconnecting substrate,
the width of a portion of each of the interconnects positioned at the wide portion may be wider than the width of a portion thereof positioned at the narrow portion.
This makes it possible to vary the pitch of interconnects, utilizing a configuration for preventing warping of the base substrate.
(8) With the above described flexible interconnecting substrate,
a pitch of the interconnects adjoining each other at the wide portions may be wider than the pitch thereof at the narrow portions.
This makes it possible to vary the pitch of interconnects, utilizing a configuration for preventing warping of the base substrate.
(9) With the above described flexible interconnecting substrate,
a slit may be formed in the base substrate so as to extend in the widthwise direction thereof.
This configuration ensures that the formation of a slit makes it easy to bend the base substrate.
(10) With the above described flexible interconnecting substrate,
the slit may be formed in a region where the wide portion is formed.
This configuration ensures that the slit is formed in a region where a wider portion of the interconnect is formed, in other words, where a portion of the interconnect that is stronger is formed. Therefore, forming the slit ensures that breakages are prevented by the increased strength of the interconnect itself, even if the strength of the base substrate or the strength that supports the interconnect should decrease.
(11) With the above described flexible interconnecting substrate,
each of the interconnecting patterns may have an electrically connecting portion to a semiconductor chip, and may be formed in regions extending in a plurality of directions from the electrically connecting portion,
the narrow portion and the wide portion being formed in at least one of the regions.
In other words, each of the interconnecting patterns is formed to extend in two directions from the electrically connecting portion as the center. The narrow portion and the wide portion of the interconnecting pattern are formed within at least one of the extending regions.
(12) With the above described flexible interconnecting substrate,
each of the interconnecting patterns may have a first terminal for external connection that is formed in a region extending in one direction from the electrically connecting portion and a second terminal for external connection that is formed in a region extending in another direction from the electrically connecting portion, and
the narrow portion and the wide portion may be formed between the electrically connecting portion and at least one of the first and second terminals.
The provision of the narrow portion and the wide portion for removing warping of the base substrate prevents at least one position of the first and second terminals from being wrongly positioned.
(13) With the above described flexible interconnecting substrate,
a plurality of device holes may be formed in the base substrate, and
the electrically connecting portion may comprise a plurality of leads protruding into each of the device holes.
(14) The above-described flexible interconnecting substrate may comprise a protective film covering the interconnecting patterns,
wherein the width of the protective film in the widthwise direction of the base substrate may be formed to be wider in a region covering the wide portion and narrower in a region covering the narrow portion.
This makes it possible to form the protective film to be narrow in a region that covers the narrow portion, restraining the effects of expansion and contraction of the protective film with respect to the base substrate. In other words, the region in which the protective film is formed is reduced, making it possible to restrain the amount of thermal contraction of the protective film, even when the flexible interconnecting substrate is subjected to a heating step, and thus making it possible to reduce the amount of warping of the base substrate.
(15) With the above described flexible interconnecting substrate,
each of the interconnects may extend by repeating a reciprocal bend to the left and the right.
(16) A film carrier in accordance with the present invention could be obtained by cutting the base substrate of the flexible interconnecting substrate described above, at lines extending in the widthwise direction of the base substrate.
(17) A tape-shaped semiconductor device in accordance with the present invention comprises:
the above described flexible interconnecting substrate; and
a plurality of semiconductor chips connected electrically to the interconnecting pattern of the flexible interconnecting substrate.
(18) A semiconductor device in accordance with the present invention is obtained by cutting the base substrate of the tape-shaped semiconductor device at lines extending in the widthwise direction, on both sides of one of the semiconductor chips.
Such a semiconductor device is not limited to one obtained by cutting the base substrate of the above described tape-shaped semiconductor device, it can also apply to any semiconductor device having a similar configuration and form to one obtained by cutting.
(19) A semiconductor device as another aspect of the present invention is obtained by punching-out the base substrate of the tape-shaped semiconductor device around an outline that encompasses one of the semiconductor chips.
Such a semiconductor device is not limited to one obtained by punching out the base substrate of the above described tape-shaped semiconductor device; it can also apply to any semiconductor device having a similar configuration and form to one obtained by punching.
(20) A circuit board in accordance with the present invention is connected electrically to the above described semiconductor device.
(21) With the above described circuit board,
the base substrate of the semiconductor device may be provided so as to bend around an edge of the circuit board.
(22) With the above described circuit board,
the base substrate of the semiconductor device may be provided with the slit described above,
the slit of the base substrate may be disposed at the edge of the circuit board, and
a portion of the base substrate forming the slit, may bend.
(23) The above-described circuit board could be formed as a liquid crystal panel.
(24) Electronic equipment in accordance with the present invention has a semiconductor device.
(25) A method of manufacturing a flexible interconnecting substrate in accordance with the present invention comprises a step of forming a plurality of interconnecting patterns on a base substrate of an elongate form, wherein:
each of the interconnecting patterns has a plurality of interconnects, and
a portion of each of interconnects is formed to extend in a direction of a first side edge of a widthwise direction of the base substrate, and another portion of the interconnects is formed to extend in a direction of a second side edge of the widthwise direction of the base substrate, the directions of the first and second side-edges crossing with a longitudinal axis of the base substrate.
Note that in this aspect of the invention, xe2x80x9cinterconnectxe2x80x9d indicates a portion in contact with at least two electrical contact points and xe2x80x9cinterconnecting patternxe2x80x9d indicates all of a plurality of interconnects comprised within one final product (such as a semiconductor device). A flexible interconnecting substrate in accordance with the present invention comprises a plurality of interconnecting patterns for manufacturing a plurality of final products.
With this aspect of the invention, interconnects have portions that extend to the right and left, so that the interconnects provide support in a plurality of directions even if the base substrate expands or contracts, thus making it possible to reduce warming of the base substrate.